Tuesday, January 25, 2005

"YAKIMA, Wash. (AP) - Researchers at a national science laboratory in south-central Washington have found a way to achieve in days what takes Mother Nature millions of years - converting wood to mineral.

The ability to make petrified wood could hold promise for separating industrial chemicals, filtering pollutants and soaking up contamination, said Yongsoon Shin, research scientist at the Pacific Northwest National Laboratory.

'Wood petrified is very hard and very porous material - it's not really a wood component,' Shin said Monday in a telephone interview. As a mineral product, petrified wood has a large, hard surface and a porous inside, making it ideal to soak up or separate substances or act as a catalyst in other processes, he said.

Natural petrified wood occurs when trees are buried without oxygen, then leach their wood components and soak up the soil's minerals. For instance, at the Ginkgo Petrified Forest, a state park on the west shore of the Columbia River in central Washington, trees were believed to have been buried without oxygen beneath molten lava millions of years ago.

To create petrified wood, the researchers bought pine and poplar boards at a lumber yard. They gave a half-inch cube of wood an acid bath, then soaked it in a silica solution for days. The wood was air-dried, cooked in an argon-filled furnace at temperatures as high as 1,400 degrees and cooled in argon to room temperature.

The colorless, odorless element argon is sometimes used as a protective atmosphere for growing certain crystals.

The result was a new silicon carbide that exactly replicates petrified wood, Shin said.

The results of the research were published in the latest edition of the journal Advanced Materials.

The researchers now are focused on trying to create narrow, ordered pores in the silicon carbide to make the material even more porous, which would make it even more useful in the industrial world, Shin said.

'If pores are too big or too small, it's not too useful,' he said.

The Richland lab is a research center operated by the U.S. Department of Energy. It works on complex problems in energy, national security, the environment and life sciences. The laboratory employees nearly 4,000 people and has a $650 million annual budget. "